JP7785255B2 - Hydride ion conductor and its manufacturing method, catalyst, battery electrolyte, and battery - Google Patents

Description

The present invention relates to a hydride ion conductor and its manufacturing method, a catalyst, a battery electrolyte, and a battery.

In recent years, research into the synthesis and properties of compounds containing hydride ions (H ⁻ ) has progressed.
H ⁻ is monovalent, has high polarizability, and has a low redox potential (E ⁰ = −2.25 V vs. SHE), and is therefore expected to be used in, for example, high-energy-density electrochemical devices and as intermediates for other mixed anion compounds.
For example, layered perovskite-type oxyhydrides (La,Sr) ₂ Li(O,H) ₄ and BaH ₂ in the high-temperature phase are known as solid compounds that exhibit high H ^{-conductivity} , and it has been discussed that factors such as crystal structure and anion deficiency affect ionic conduction.

Patent Document 1 describes a metal-supported material comprising a transition metal and a carrier that supports the transition metal, characterized in that the carrier is a metal hydride represented by a specific formula.
Patent Document 2 describes a hydride ion conductor having a composition represented by the general formula M ¹ _XM ² _{yAH z} O _α (wherein M ¹ represents a trivalent rare earth element, M ² represents an alkaline earth metal element or Mg, and A represents Li, Na, Sc, Co, Ni, Cu, Mn, or Fe; 0≦x≦2; 0≦y≦2; x+y=2; 0<z<4; and 1≦α<3 or 3<α<4).
Patent Document 3 describes a perovskite-type oxide having hydride ion conductivity, in which 1 atomic % or more of the oxide ions contained in the titanium-containing perovskite-type oxide are substituted with hydride ions (H ⁻ ).

International Publication No. 2017/082265 Japanese Patent Application Laid-Open No. 2017-098067 International Publication No. 2013/008705

As described above, various solid compounds that exhibit hydride ion conductivity have been investigated to date.
However, since various physical properties are required of hydride ion conductors depending on the application in which they are used, the development of novel hydride ion conductors is desired.

The object of the present invention is to provide a novel hydride ion conductor, a catalyst comprising the hydride ion conductor, a battery electrolyte comprising the hydride ion conductor, and a battery comprising the battery electrolyte.

Representative embodiments of the present invention are described below.
<1> A hydride ion conductor having a composition represented by formula (1): M ¹ _a M ² _b M ³ _c H _x X ¹ _y X ² _z ;
In formula (1), ^M1 represents an alkali metal element, ^M2 represents Mg or an alkaline earth metal element, ^M3 represents a rare earth metal element, 0≦a≦1, 0≦b≦2, 0≦c≦2, 1<a+b+c≦2, 0<x<4, ^X1 is a halogen element, 0≦y<4, ^X2 is a chalcogen element, when ^X2 represents only oxygen, 0≦z<1, when ^X2 represents an element containing a chalcogen element other than oxygen, 0≦z<3, 3<x+y+z≦5, and each of ^M1 , ^M2 , ^M3 , ^X1 , and ^X2 may contain multiple elements.
<2> The hydride ion conductor according to <1>, which does not contain oxygen atoms or contains oxygen atoms in an amount of 5% or less by mole relative to the total molar amount of ^X1 and ^X2 .
<3> The hydride ion conductor according to <1> or <2>, wherein the absolute value of a+2b+3c-(x+y+2z) is 1 or less.
<4> The hydride ion conductor according to any one of <1> to <3>, which is a layered compound, and in which elements present in the layered compound among H, ^X1 , and ^X2 in the formula (1) are present between the layered lattices.
<5> The hydride ion conductor according to any one of <1> to <4>, wherein a=0 in formula (1).
<6> The hydride ion conductor according to any one of <1> to <5>, wherein in formula (1), 0<b≦2, and M ² contains at least one of Ba and Sr.
<7> The hydride ion conductor according to any one of <1> to <6>, wherein in formula (1), 0<c≦2 and ^M3 contains La.
<8> The hydride ion conductor according to any one of <1> to <7>, wherein, in formula (1), 0≦c≦1 and 1≦b≦2.
<9> The hydride ion conductor according to any one of <1> to <8>, wherein in formula (1), 0<y<4, and X ¹ contains F, Cl, or Br.
<10> The hydride ion conductor according to any one of <1> to <9>, wherein in formula (1), 0<z<3, and X ² contains S or Se.
<11> The hydride ion conductor according to any one of <1> to <10>, which has a composition represented by the following formula (1′):
Formula (1'): M ¹ _a-δ1 M ² _b-δ2 M ³ _c-δ3 H _{x-(δ1+2δ2+3δ3)} X ¹ _y X ² _z
In formula (1'), ^M1 represents an alkali metal element, ^M2 represents Mg or an alkaline earth metal element, ^M3 represents a rare earth metal element, 0≦a≦1, 0≦b≦2, 0≦c≦2, 1<a+b+c≦2, 0<x<4, ^X1 is a halogen element, 0≦y<4, ^X2 is a chalcogen element, when ^X2 represents only oxygen, 0≦z<1, when ^X2 represents an element containing a chalcogen element other than oxygen, 0≦z<3, 3<x+y+z≦5, and ^M1 , ^M2 , ^M3 , ^X1 and X Each of ^{δ1 and δ2} may contain a plurality of elements, δ1 is 0.1 or more, δ2 is 0.1 or more, δ3 is 0.1 or more, and a1-δ1, b1-δ2, c1-δ3, and x-(δ1+2δ2+3δ3) are not less than 0.
<12> A method for producing the hydride ion conductor according to any one of <1> to <11>,
A step of heating a precursor powder containing at least one hydride composed of a binary system of A-H and at least one compound composed of a binary system of A-X under a pressure condition of less than 1 GPa,
A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
Method for producing hydride ion conductors.
<13> A method for producing the hydride ion conductor according to any one of <1> to <11>,
a step of heating a precursor powder containing at least one hydride composed of a binary system of A-H and at least one compound composed of a binary system of A-X under a pressure condition of 1 GPa or more,
A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
Method for producing hydride ion conductors.
<14> A catalyst comprising the hydride ion conductor according to any one of <1> to <11>.
<15> A battery electrolyte containing the hydride ion conductor according to any one of <1> to <11>.
<16> A battery comprising the battery electrolyte according to <15>.

The present invention provides a novel hydride ion conductor, a catalyst comprising the hydride ion conductor, a battery electrolyte comprising the hydride ion conductor, and a battery comprising the battery electrolyte.

1 shows the results of synchrotron radiation powder X-ray diffraction measurement of Ba ₂ H ₃ Cl, Ba ₂ H ₃ Br, and Ba ₂ H ₃ I obtained in Production Example 1. 1 shows the results of synchrotron radiation powder X-ray diffraction measurement (XRD) of LaSrH3S obtained in Production Example 4. 1 shows the results of synchrotron radiation powder X-ray diffraction measurement (XRD) of Sr ₇ H ₁₂ Cl ₂ (Sr ₂ H _3.43 Cl _0.57 ) obtained in Production Example 5. 1 shows _{the results} of _{electrochemical impedance} measurement (Arrhenius plots ₎ of _Ba2H3Cl , _Ba2H3Br , and _Ba2H3I obtained in Production Example 1, _{Ba1.9K0.1H2.9Cl} obtained in Production Example ₃ , and _LaSrH3S and LaBaH3S obtained in Production Example 4. 1 shows the results (Arrhenius plots) of electrochemical impedance measurements of Ba ₂ H ₃ Cl, Ba ₂ H ₃ Br, and Ba ₂ H ₃ I obtained in Production Example 1 during temperature increase and decrease. 1 shows the results of electrochemical impedance measurement (Cole-Cole plot) of Ba ₂ H ₃ I (200° C.) obtained in Production Example 1. 1 shows the results (Arrhenius plot) of electrochemical impedance measurement of Ba ₂ H ₃ X (X=Cl, Br, I) obtained in Production Example 6.

The present invention will be described in detail below. The following description of the components will be based on representative embodiments and specific examples of the present invention, but the present invention is not limited to such embodiments and specific examples.
In this specification, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In this specification, unless otherwise specified, the temperature is 23° C. and the pressure is 101,325 Pa (1 atmosphere).
As used herein, combinations of preferred embodiments are more preferred embodiments.

(Hydride Conductors)
The hydride conductor of the present invention is a hydride conductor having a composition represented by the following formula (1):
Formula (1): M ¹ _a M ² _b M ³ _c H _x X ¹ _y X ² _z
In formula (1), ^M1 represents an alkali metal element, ^M2 represents Mg or an alkaline earth metal element, ^M3 represents a rare earth metal element, 0≦a≦1, 0≦b≦2, 0≦c≦2, 1<a+b+c≦2, 0<x<4, ^X1 is a halogen element, 0≦y<4, ^X2 is a chalcogen element, when ^X2 represents only oxygen, 0≦z<1, when ^X2 represents an element containing a chalcogen element other than oxygen, 0≦z<3, 3<x+y+z≦5, and each of ^M1 , ^M2 , ^M3 , ^X1 , and ^X2 may contain multiple elements.

The hydride conductor of the present invention is a novel hydride conductor.
None of Patent Documents 1 to 3 describes a hydride conductor that corresponds to formula (1) of the present invention.
Patent Document 1 describes a hydride ion conductor such as _BaH2 having the formula: XHn (wherein X represents at least one atom selected from Group 2 atoms, Group 3 atoms, and lanthanoid atoms in the periodic table, and n represents a number satisfying the formula 2≦n≦3). However, this differs from the hydride ion conductor of the present invention in that it does not contain a halogen element or a chalcogen element.
Patent Document 2 describes a hydride ion conductor having a composition represented by the formula M ¹ _XM ² _{yAH z} O _α (wherein M ¹ represents a trivalent rare earth element, M ² represents an alkaline earth metal element or Mg, and A represents Li, Na, Sc, Co, Ni, Cu, Mn, or Fe; 0≦x≦2; 0≦y≦2; x+y=2; 0<z<4; and 1≦α<3 or 3<α<4). However, this hydride ion conductor differs from the hydride ion conductor of the present invention in that it contains a total of three metal elements (M ¹ , M ² , and A).
Patent Document 3 describes a perovskite-type oxide having hydride ion conductivity, in which 1 atomic % or more of the oxide ions contained in the titanium-containing perovskite-type oxide are substituted with hydride ions (H-). However, this perovskite-type oxide differs from the hydride ion conductor of the present invention in that titanium is an essential metal element.
Furthermore, the hydride conductor of the present invention, having the composition represented by the formula (1), is considered to have superior hydride ion conductivity compared to the hydride ion conductors described in any of the above-mentioned Patent Documents 1 to 3. In particular, some hydride conductors of the present invention are capable of exhibiting hydride ion conductivity within or near the so-called "Norby gap," which is the limit region of ionic conductivity of hydrogen cations due to the large charge density of hydrogen cations.
Furthermore, the hydride conductor of the present invention has the composition represented by formula (1) and is therefore considered to have excellent hydride ion conductivity even at low temperatures (for example, in the medium-low temperature range of 300° C. or lower) compared to, for example, the hydride ion conductors described in any of Patent Documents 1 to 3.
In addition, since the hydride conductor of the present invention has the composition represented by the formula (1), electron donation from hydride ions is suppressed compared to the hydride ion conductors described in, for example, any of Patent Documents 1 to 3, and therefore, it is considered to have excellent stability.
The hydride conductor of the present invention will be described in detail below.

<M ¹ , a>
In formula (1), ^M1 represents an alkali metal element, and examples thereof include Li, Na, K, Rb, Cs, and Fr, and Li, Na, K, or Rb is preferred, with K being more preferred.
In formula (1), a satisfies 0≦a≦1, preferably 0≦a≦0.8, and more preferably 0≦a≦0.5.
By containing ^M1 within the range of a, excellent hydride ion conductivity may be obtained.
An embodiment in which a=0 is also one of the preferred embodiments of the present invention.

<M ² , b>
In formula (1), ^M2 represents Mg or an alkaline earth metal element, such as Mg, Ca, Sr, Ba, or Ra, preferably Ca, Sr, or Ba, and more preferably Sr or Ba.
In formula (1), b satisfies 0≦b≦2, preferably 0.5≦b≦2, more preferably 0.8≦b≦2, and further preferably 1≦b≦2.
Furthermore, an embodiment in which 0<b≦2 and ^M2 contains at least one of Ba and Sr is also one of the preferred embodiments of the present invention.
In the above-mentioned embodiment, the preferred embodiment of b is as described above.

<M ³ , c>
In formula (1), ^M3 represents a rare earth metal element, and examples thereof include Sc, Y, and lanthanoids, with Sc, Y, and La being preferred, and La being more preferred.
Furthermore, when the compound represented by formula (1) contains ^M3 (i.e., 0<c), it is preferable that the compound represented by formula (1) contains ^M2 (i.e., 0<b).
In formula (1), c satisfies 0≦c≦2, preferably 0≦c≦1.5, more preferably 0≦c≦1.2, and further preferably 0≦c≦1.
Furthermore, an embodiment in which 0<c≦2 and ^M3 contains La is also one of the preferred embodiments of the present invention.
Furthermore, an embodiment in which 0≦c≦1 and 1≦b≦2 is also one of the preferred embodiments of the present invention.
In the above embodiment, an embodiment in which 0≦c≦0.5 and 1.5≦b≦2 is also one of the preferred embodiments of the present invention.

＜x＞
In formula (1), x satisfies 0<x<4, preferably 1≦x<4, and more preferably 2≦x≦3.

<X ¹ , y>
In formula (1), ^X1 represents a halogen element, and examples thereof include F, Cl, Br, I, and At. From the viewpoint of improving the degree of freedom of movement of hydride ions and improving hydride conductivity, Cl, Br, or I is preferred, and I is more preferred.
In particular, it is believed that the hydride conductivity is likely to increase when ^X1 is a soft anion (whose bond length is easily variable) such as Cl, Br, or I. Among these, I is the softest and therefore most preferred, and Br is the next softest and therefore second most preferred.
The value of y is 0≦y<4, preferably 0≦y≦3, and more preferably 0≦y≦1.
Furthermore, an embodiment in which 0<y<4 and X ¹ contains F, Cl or Br is also one of the preferred embodiments of the present invention.

<X ² , z>
In formula (1), ^X2 represents a chalcogen element, and examples of the chalcogen element include O, S, Se, Te, Po, and Lv. From the viewpoint of the degree of freedom of movement of hydride ions, S, Se, or Te is preferred, and S or Se is more preferred.
In formula (1), when ^X2 represents only oxygen, z satisfies 0≦z<1, preferably 0≦z≦0.9, more preferably 0≦z≦0.8, and further preferably 0≦z≦0.6.
In formula (1), when ^X2 represents an element containing a chalcogen element other than oxygen, z satisfies 0≦z<3, preferably 0≦z≦2, and more preferably 0≦z≦1.
Furthermore, the hydride ion conductor of the present invention may contain only one of ^X1 and ^X2 , or may contain both ^X1 and ^X2 , but preferably contains only one of ^X1 and ^X2 . That is, an embodiment in which 0<y and z=0, or an embodiment in which y=0 and 0<z, is also one of the preferred embodiments.
Furthermore, from the viewpoint of improving the conductivity of hydride ions, it is preferable that the hydride ion conductor of the present invention does not contain oxygen atoms or that the molar amount of oxygen atoms contained is 5% or less relative to the total molar amount of ^X1 and ^X2 .
Furthermore, an embodiment in which 0<z<3 and ^X2 contains S or Se is also one of the preferred embodiments of the present invention.
The molar content of oxygen atoms is more preferably 2% or less, even more preferably 1% or less, and particularly preferably 0.1% or less.

<a+b+c>
In formula (1), a+b+c satisfies 1<a+b+c≦2, preferably 1.5<a+b+c≦2, more preferably 1.8<a+b+c≦2, and even more preferably 1.9<a+b+c≦2.
In addition, an embodiment where a+b+c=2 in formula (1) is also one of the preferred embodiments of the present invention.

<Absolute value of a+2b+3c-(x+y+2z)>
The absolute value of a+2b+3c-(x+y+2z) in formula (1) is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less.
The minimum absolute value of the a+2b+3c-(x+y+2z) is not particularly limited as long as it is equal to or greater than 0. In addition, an embodiment in which the absolute value of the a+2b+3c-(x+y+2z) is 0 is also one of the preferred embodiments of the present invention.

<Structure>
The structure of the hydride conductor of the present invention is thought to be distorted depending on temperature conditions and the like, and it is difficult to uniquely define the structure. However, the hydride conductor of the present invention is preferably a layered compound, and more preferably a layered compound in which the elements present in the layered compound, among H, ^X1 and ^X2 in formula (1), are present between the layered lattices.
An example of the hydride conductor of the present invention is a hexagonal compound in which the elements present in the layered compound, among H, ^X1 and ^X2, are arranged between the layered lattices.
A presumed crystal structure of Ba ₂ H ₃ X, which corresponds to the hydride ion conductor of the present invention, is described below, but the crystal structure of the hydride ion conductor of the present invention is not limited to this.

The crystal structure of Ba ₂ H ₃ X is the anti-Li ₃ LaSb ₂ structure (space group P3m1), consisting of face-sharing octahedral layers of HBa 6 and XBa ₆ stacked alternately along the hexagonal C-axis, with additional hydride anions in distorted tetrahedra (HBa 4 ). It can also be considered as anion-ordered HT-BaH ₂ in which half of the H 1 s are replaced by X s.

<Impurities>
The hydride conductor of the present invention may contain elements different from M ¹ , M ² , M ³ , H, X ¹ , and X ² as inevitable impurities. The ratio of the molar amount of the inevitable impurities contained in the hydride conductor of the present invention to the total molar amount of the elements M ¹ , M ² , M ³ , H, X ¹ , and X ² contained in the hydride conductor of the present invention is preferably 10% or less, more preferably 5% or less, even more preferably 1% or less, and particularly preferably 0.1% or less. The lower limit of this ratio is not particularly limited and may be 0%. Inevitable impurities refer to elements that are inevitably mixed in during the production process, for example, because they are mixed in with raw materials.

<Defects>
The hydride ion conductor having the composition represented by formula (1) may have defects.
Specifically, for example, the composition formula Ba ₂ H ₃ X is considered to be a composition having Schottky defects of Ba and H, which is actually expressed as Ba _2-δ H _3-2δ X (δ is the amount of defect).
The range of δ is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be set to, for example, 0.5. An embodiment in which δ is 0 is also one of the preferred embodiments of the present invention.
That is, the hydride ion conductor having the composition represented by formula (1) is also preferably a hydride ion conductor having the composition represented by the following formula (1').
Formula (1'): M ¹ _a-δ1 M ² _b-δ2 M ³ _c-δ3 H _{x-(δ1+2δ2+3δ3)} X ¹ _y X ² _z
In formula (1'), M ¹ , M ² , M ³ , a, b, c, X ¹ _, X ² _, x, y, and z have the same meanings as M ¹ , M ² , M ³ , a, b, c, X ¹ _, X ² _, x, y, and z in formula (1), respectively, and preferred embodiments are also the same. However, a1-δ1, b1-δ2, c1-δ3, and x-(δ1+2δ2+3δ3) are not all less than 0.
In formula (1'), δ1 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ1 is 0 is also one of the preferred embodiments of the present invention.
In formula (1'), δ2 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ2 is 0 is also one of the preferred embodiments of the present invention.
In formula (1'), δ3 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ3 is 0 is also one of the preferred embodiments of the present invention.
In formula (1'), at least one selected from the group consisting of H, ^X1 , and ^X2 may randomly occupy an atomic position occupied by at least one other selected from the group consisting of H, ^X1 , and ^X2 . That is, the hydride ion conductor of the present invention can have so-called antisite defects of H, ^X1 , and ^X2 .
The above-mentioned occupancy ratio (the ratio of sites occupied by ^X1 or ^X2 among all sites ideally occupied by H) is, for example, preferably 10% or more, and more preferably 20% or more. The upper limit of the above-mentioned ratio is not particularly limited, but can be 50% or less. Furthermore, an embodiment in which the above-mentioned ratio is 0% is also one of the preferred embodiments of the present invention.
For example, the hydride ion conductor having the composition represented by formula (1') may be a hydride ion conductor having the composition represented by formula (1'').
Formula (1''): M ¹ _a-δ1 M ² _b-δ2 M ³ _c-δ3 (H _{x-(δ1+2δ2+3δ3)} ) ^H _1-α (X ¹ _y X ² _z ) ^H _α (H _{x-(δ1+2δ2+3δ3)} ) ^X _α (X ¹ _y X ² _z ) ^X _1-α
However, for example, (A) ^B _α indicates that A occupies a site that would ideally be occupied by B at a ratio of α.
In formula (1"), ^M1 , ^M2 , ^M3 , a, b, c, ^X1 _, ^X2 , x _, y, z, δ1, δ2, and δ3 have the same meanings as ^M1 , ^M2 , ^M3 , a, b, c, ^X1 , ^X2 _, x, y _, z, δ1, δ2, and δ3 in formula (1'), respectively, and preferred embodiments are also the same.
α is preferably 0.1 or more, more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which α is 0 is also one of the preferred embodiments of the present invention.

<Activation energy>
The activation energy of the compound represented by formula (1) is preferably 60 kJ mol or ^less , more preferably 55 kJ mol or ^less , and even more preferably 50 kJ mol or ^less . There is no particular lower limit, but it can be, for example, 20 kJ mol or ^more , and preferably ³⁰ kJ mol or more.
It is believed that the small activation energy allows high-speed conduction of hydride anions in a lower temperature range.

<Equations (2) to (4)>
Among these, the compound represented by formula (1) is preferably a compound represented by any one of the following formulas (2) to (4).

Formula (2): M ² ₂ H _x X ¹ _y
In formula (2), ^M2 represents Mg or an alkaline earth metal element, 0<x<4, ^X1 represents a halogen element, 0≦y<4, and 3< _{x+y≦5, and M2 and X1 may each contain a plurality of elements. In particular, Ba2H3X} ^{( X} ₌ Cl, Br, I) can exhibit hydride ion conductivity within or near the Norby gap, and can also exhibit suitable hydride ion conductivity even in a low temperature region.
Furthermore, when the compound represented by formula (2) contains defects, it may be a compound represented by the following formula (2').
Formula (2'): M ² _2-δ H _x-δ X ¹ _y
In formula (2'), M ² , X ¹ , x, and y are the same as M ² , X 1 , x, and y in formula (2), provided that 2-δ and x-δ are not 0 or less.
In formula (2'), δ is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ is 0 is also one of the preferred embodiments of the present invention. Furthermore, the compound represented by formula (2') can have so-called antisite defects of H and ^X1 .

Formula (3): M ¹ _a M ² _b H _x X ¹ _y
In formula (3), ^M1 represents an alkali metal element, ^M2 represents Mg or an alkaline earth metal element, 0<a≦1, 0<b<2, 1<a+b≦2, 0<x<4, ^X1 represents a halogen element, 0≦y<4, 3<x+y≦5, and each of ^M1 , ^M2 , and ^X1 may contain multiple elements.
When the compound represented by formula (3) contains defects, it may be a compound represented by the following formula (3').
Formula (3'): M ¹ _a-δ1 M ² _b-δ2 H _x-(δ1+2δ2) X ¹ _y
In formula (3'), M ¹ , M ² , X ¹ , a, b, x, and y are the same as M ¹ , M ² , X ¹ , a, b, x, and y in formula (3), provided that a-δ1, b-δ2, and x-(δ1+2δ2) are not each 0 or less.
In formula (3'), δ1 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ1 is 0 is also one of the preferred embodiments of the present invention.
In formula (3'), δ2 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ2 is 0 is also one of the preferred embodiments of the present invention. Furthermore, the compound represented by formula (3') can have so-called antisite defects of H and ^X1 .

Formula (4): M ² _b M ³ _c H _x X ² _z
In formula (4), ^M2 represents Mg or an alkaline earth metal element, ^M3 represents a rare earth metal element, 0<b<2, 0<c<2, 1<b+c≦2, 0<x<4, ^X2 is a chalcogen element, and when ^X2 represents only oxygen, 0≦z<1, and when ^X2 represents an element containing a chalcogen element other than oxygen, 0≦z<3 and 3<x+z≦4, and ^M2 , ^M3 , and ^X2 may each contain multiple types of elements.
Furthermore, when the compound represented by formula (4) contains defects, it may be a compound represented by the following formula (4').
Formula (4'): M ² _b-δ2 M ³ _c-δ3 H _{x-(2δ2+3δ3)} X ² _z
In formula (4'), M ² , M ³ , X ² , b, c, x, and z are the same as M ² , M ³ , X ² , b, c, x, and z in formula (4), provided that b-δ2, c-δ3, and x-(2δ2+3δ3) are not each 0 or less.
In formula (4'), δ2 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ2 is 0 is also one of the preferred embodiments of the present invention.
In formula (4'), δ3 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. The upper limit is not particularly limited, but can be, for example, 0.5. An embodiment in which δ3 is 0 is also one of the preferred embodiments of the present invention. Furthermore, the compound represented by formula (4') can have so-called antisite defects of H and ^X2 .

[Formula (2)]
In formula (2), M ² , x, X ¹ and y have the same meanings as M ² , x, X ¹ and y in formula (1), respectively, and the preferred embodiments are also the same.
In formula (2), 3<x+y≦5, preferably 3.8<x+y≦5, more preferably 3.9<x+y≦4, and particularly preferably x+y=4.

[Formula (3)]
In formula (3), M ¹ , M ² , x, X ¹ and y have the same meanings as M ¹ , a, M ² , b, x, X ¹ and y in formula (1), respectively, and preferred embodiments are also the same.
In formula (3), a satisfies 0<a≦1, preferably 0.05≦a≦1, and more preferably 0.05≦a≦0.5.
In formula (3), b satisfies 0<b<2, preferably 1<b<2, more preferably 1≦b≦1.95, and even more preferably 1.5≦b≦1.95.
In formula (3), a+b satisfies 1<a+b≦2, preferably 1.5<a+b≦2, more preferably 1.8<a+b≦2, and even more preferably 1.9<a+b≦2.
Furthermore, an embodiment in which a+b=2 is also one of the preferred embodiments of the present invention.
The absolute value of a+2b-(x+y) in formula (3) is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less.
The minimum absolute value of the a+2b-(x+y) is not particularly limited as long as it is equal to or greater than 0. In addition, an embodiment in which the absolute value of a+2b-(x+y) is 0 is also one of the preferred embodiments of the present invention.

[Formula (4)]
In formula (4), M ² , M ³ , x, X ² and z have the same meanings as M ² , M ³ , x, X ² and z in formula (1), respectively, and preferred embodiments are also the same.
In formula (4), b satisfies 0<b<2, preferably 0.2≦b<1.8, and more preferably 0.5≦b≦1.5.
In formula (4), c satisfies 0<c<2, preferably 0.2≦c<1.8, and more preferably 0.5≦c≦1.5.
In formula (4), b+c satisfies 1<b+c≦2, preferably 1.5<b+c≦2, more preferably 1.8<b+c≦2, and even more preferably 1.9<b+c≦2.
An embodiment in which b+c=2 is also one of the preferred embodiments of the present invention.
The absolute value of 2b+3c-(x+2z) in formula (4) is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less.
The minimum absolute value of 2b+3c-(x+2z) is not particularly limited as long as it is equal to or greater than 0. In addition, an embodiment in which the absolute value of 2b+3c-(x+2z) is 0 is also one of the preferred embodiments of the present invention.

<Conductivity>
The hydride conductivity of the hydride conductor of the present invention is preferably 1×10 ⁻⁴ S/cm or more, more preferably 1×10 ⁻³ S/cm at 300° C. There is no particular upper limit, but it is, for example, 1×10 ⁻¹ S/cm.
The hydride conductivity of the hydride conductor of the present invention is preferably 1×10 ⁻⁶ S/cm or more, more preferably 1×10 ⁻⁵ S/cm, at 100° C. There is no particular upper limit, but it is, for example, 1×10 ⁻¹ S/cm.
The hydride conductivity is measured by the method described in the Examples below.

<Specific examples>
Specific examples of _the compound represented by formula (1) include, _{but are not limited to , Ba2H3Cl , Ba2H3Br , Ba2H3I} , _{Ba1.9K0.1H2.9Cl} , _LaSrH3S , _LaBaH3S , _Ba2H3.5I0.5 , _{La0.1Ba1.9H3.1Cl} , _Sr2H3.4Cl0.6 ( _{Sr7H12Cl2 )} , _{and the like} .

<Method for producing the compound represented by formula (1)>
An example of a method for producing a hydride ion conductor having the composition represented by formula (1) is shown below. However, the method for producing the hydride ion conductor having the composition represented by formula (1) is not particularly limited as long as it has the composition represented by formula (1), and the hydride ion conductor may be obtained by any other method.

A first aspect of the method for producing a hydride ion conductor of the present invention comprises a step of heating a precursor powder containing at least one hydride composed of an A-H binary system and at least one compound composed of an A-X binary system under a pressure condition of less than 1 GPa, wherein A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
According to the first embodiment, the hydride ion conductor of the present invention is obtained as a powder sample.
The precursor powder can be obtained by thoroughly mixing, for example, a hydride consisting of a binary system of A-H (e.g., NaH, BaH ₂ , LaH ₃ , etc.) and a compound consisting of a binary system of A-X (e.g., NaBr, BaI ₂ , La ₂ S ₃ , etc.).
The binary hydride of A-H and the binary compound of A-X may each be used alone or in combination of two or more.
For example, by using BaH ₂ and KH in combination as a hydride consisting of a binary system of AH, a hydride conductor containing K as M ¹ and Ba as M ² in formula (1) can be obtained.
The heating is preferably carried out in an inert gas atmosphere such as hydrogen gas, nitrogen gas, or argon gas, or a mixed gas atmosphere of these, or in vacuum.
Furthermore, it is preferable that the handling of the A-H binary hydride and the A-X binary compound in the mixing or the like for preparing the precursor powder is also carried out under the inert gas atmosphere or under vacuum.
The heating is carried out, for example, at 200 to 1600° C. for 0.1 to 100 hours. The heating means is not particularly limited, and heating may be carried out by a known method.
The pressure condition during the heating may be less than 1 GPa, preferably 10 to 500 kPa, more preferably 50 to 200 kPa, and even more preferably 90 to 110 kPa. It is also preferable to perform the heating under normal pressure (101.325 kPa).
The pressure conditions can be applied by a known method such as a pressure generator, and are not particularly limited. When the reaction is carried out under normal pressure, the reaction can be carried out without any particular adjustment of the pressure.

A second aspect of the method for producing a hydride ion conductor of the present invention comprises a step of heating a precursor powder containing at least one hydride composed of a binary system of A-H and at least one compound composed of a binary system of A-X under a high pressure condition of 1 GPa or more, wherein A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
According to the second embodiment, the hydride ion conductor of the present invention is obtained as a powder sample.
The pressure under the high pressure condition may be 1 GPa or more, preferably 2 GPa or more, more preferably 3 GPa or more, and even more preferably 5 GPa or more. The upper limit of the pressure is not particularly limited, but can be, for example, 20 GPa or less. The pressure condition can be applied by a known method such as a pressure generator, and is not particularly limited.
In this way, when heating is performed under high pressure conditions, there is an advantage that the composition of the hydride ion conductor can be easily controlled.
For example, the hydride ion conductor of the present invention can be said to be a composite anion system containing hydride ions and at least one other anion. In such a composite anion system, there may be differences in volatility between the anions. Therefore, by performing the heating under the high-pressure conditions, the volatilization of the anions is suppressed, making it easier to control the composition. Furthermore, compounds that are difficult to synthesize under low-pressure conditions, such as atmospheric pressure, may be synthesized under high-pressure conditions, which is thought to broaden the range of compositions that can be synthesized.
The binary hydride of AH, the binary compound of AX, the heating conditions, etc. are the same as those in the first embodiment.
In the second embodiment, a hydrogen generating agent (for example, a mixture of NaBH ₄ and Ca(OH) ₂ ) may be added to the precursor powder to compensate for hydrogen deficiency in the product or to control the synthesis atmosphere.

The hydride ion conductor of the present invention may be produced in a powder state and then compressed into pellets for use, or may be mixed with a known binder or the like for use in a thick film. It can also be used in a thin film form by a vapor deposition process such as sputtering.

(catalyst)
The catalyst of the present invention is a catalyst comprising the hydride ion conductor of the present invention.
The hydride ions contained in the hydride ion conductor of the present invention have a high electron donating ability, and therefore it is expected that the hydride ion conductor will be used as a highly efficient catalyst in various syntheses.
For example, it is thought that when a hydride ion conductor reacts with nitrogen molecules, the hydride ion donates an electron, cleaving the triple bond in the nitrogen molecule, and then releases an electron, forming a nitrogen-hydrogen ring bond within the hydride ion conductor. Because it is possible to cleave the strong triple bond between nitrogen atoms, this conductor could be used as a catalyst for synthesizing ammonia from nitrogen molecules (nitrogen gas), for example.
Furthermore, when considering general hydrogenation reactions, including ammonia synthesis reactions, the catalyst of the present invention is considered to be able to promote the diffusion of hydrogen atoms strongly adsorbed on the surface of the promoter particles and hydride ions within the catalyst particles due to its excellent hydride ion conductivity, thereby reducing hydrogen poisoning, which is a cause of deterioration of general hydrogenation catalysts. In this way, the ability to promote the diffusion of hydride ions on the catalyst surface and inside the catalyst makes it possible to use the catalyst as a highly efficient, long-life hydrogenation catalyst.
Regarding the use of the hydride ion conductor as a catalyst, other than the use of the hydride ion conductor of the present invention, reference can be made to, for example, the description in Science 28 Jun 2013: Vol. 340, Issue 6140, pp. 1549-1552.

(battery electrolytes, batteries)
The battery electrolyte of the present invention contains the hydride ion conductor of the present invention, and is preferably a battery electrolyte consisting of the hydride ion conductor of the present invention.
The battery electrolyte of the present invention is preferably a solid electrolyte.
The battery electrolyte of the present invention may further contain other solid electrolytes such as inorganic solid electrolytes and organic solid electrolytes.
The specific mode of use as a battery electrolyte is not particularly limited in the present invention, and a method known to those skilled in the art can be selected or adapted.

The battery of the present invention comprises the battery electrolyte of the present invention.
The battery of the present invention is preferably a secondary battery.
The battery of the present invention is preferably an all-solid-state battery.
The battery of the present invention is preferably a battery that uses hydride ions as a charge carrier, and more preferably a fuel cell.
Examples of such batteries include hydride ion secondary batteries and ammonia fuel cells.
The components of the positive electrode, negative electrode, etc. in the battery are not particularly limited, and known components can be used.
The hydride ion conductor of the present invention is chemically stable and has excellent hydride ion conductivity, and is therefore considered to be usable as a high-potential, high-capacity, and highly stable energy device.

An example of the battery of the present invention is a battery using TiH ₂ for the positive electrode, Ti for the negative electrode, and the hydride conductor of the present invention for the solid electrolyte.
In the battery, electromotive force is generated by the following electrode reaction at the positive and negative electrodes: Hydrogen released from _TiH2 is conducted as ^H- by the hydride conductor of the present invention and is absorbed into the Ti electrode.
For details of the configuration of a battery using a hydride conductor other than the use of the hydride conductor of the present invention, reference can be made to, for example, the description in Science, 18 Mar. 2016: Vol. 351, Issue 6279, pp. 1314-1317.

The following manufacturing examples and working examples further illustrate the features of the present invention. The materials, processing details, processing procedures, etc. shown below can be modified as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the manufacturing examples or working examples shown below.

<Production Example 1: Synthesis of Ba ₂ H ₃ X (X=Cl, Br, or I) by atmospheric pressure synthesis method>
_BaH2 and _BaX2 (X = Cl, Br, or I) were mixed in a mass ratio of 1:3. The pelletized sample was sealed in a vacuumed quartz tube. It was heated in an electric furnace at 650°C for 20 hours. Because _BaH2 and the product are very unstable in air, the sample was handled in a glove box with a _N2 atmosphere.

<Production Example 2: Synthesis of Ba ₂ H ₃ X (X=Cl, Br, or I) by high-pressure synthesis method>
BaH ₂ and BaX ₂ (X = Cl, Br, or I) were mixed in a mass ratio of 1:3. The pelletized sample was loaded into a high-pressure synthesis cell. The high-pressure synthesis cell used a hollow pyrophyllite block as the pressure medium, with a graphite sleeve installed inside as a heat source. To prevent contact between the graphite sleeve and the sample, a BN sleeve was placed inside, and the sample pellet was loaded inside that. A pressure of 1 GPa was applied to the high-pressure synthesis cell using a cubic anvil-type high-pressure generator. After reaching the specified pressure, the cell was heated to a temperature of 600-900°C and maintained at that temperature for 1 hour. Because BaH ₂ and the product are highly unstable in air, the sample was handled in a glove box with a N ₂ atmosphere.

<Production Example 3: Synthesis of Ba _1.9 K _0.1 H _2.9 Cl by high-pressure synthesis method>
BaH ₂ , BaCl ₂ , and KH were mixed in a mass ratio of 28:10:2. The pelletized sample was loaded into a high-pressure synthesis cell. The high-pressure synthesis cell used a hollow pyrophyllite block as the pressure medium, with a graphite sleeve installed inside as a heat source. To prevent contact between the graphite sleeve and the sample, a BN sleeve was placed inside, and the sample pellets were loaded inside that. A pressure of 1 GPa was applied to the high-pressure synthesis cell using a cubic anvil-type high-pressure generator. After reaching the specified pressure, the cell was heated to a temperature of 600-900°C and maintained at that temperature for 1 hour. Because BaH ₂ , KH, and the product are highly unstable in air, the sample was handled in a glove box with a N ₂ atmosphere.

<Production Example 4: Synthesis of LaAH ₃ S (A=Sr and Ba)>
As starting materials, the following two different combinations of materials were used:
i) La ₂ S ₃ , LaH _3-x , AH ₂ (A=Sr and Ba) in a mass ratio of 1:1:3
ii) LaH _3-x , AS (A = Sr and Ba) in a substance ratio of 1:1
The starting materials i) or ii) were mixed in a predetermined ratio, and the pelletized sample was loaded into a high-pressure synthesis cell. The high-pressure synthesis cell used a hollow pyrophyllite block as the pressure medium, with a graphite sleeve installed inside as a heat source. To prevent contact between the graphite sleeve and the sample, a BN sleeve was placed inside, and the sample pellet was loaded inside that. A hydrogen generator was used to compensate for the hydrogen deficiency in _{LaH 3-x} . A powder mixture of _{NaBH 4} and Ca(OH) ₂ in a 1:2 ratio was pelletized and loaded into the high-pressure synthesis cell. A BN pellet was sandwiched between the powder and the sample to prevent direct contact. A pressure of 1–3 GPa was applied to the high-pressure synthesis cell using a cubic anvil-type high-pressure generator. After reaching the predetermined pressure, the cell was heated to a temperature of 600–900°C and held for 1 hour. Since LaH _3-x , AH ₂ , and the product are highly unstable in air, the samples were handled in a glove box under a N ₂ atmosphere.

<Production Example 5: Synthesis of Sr ₇ H ₁₂ Cl ₂ (Sr ₂ H _3.43 Cl _0.57 )>
_SrH2 and _SrCl2 were mixed in a mass ratio of 6:1. The pelletized sample was sealed in a vacuumed quartz tube. It was heated in an electric furnace at 650°C for 20 hours. Because _SrH2 and the product are very unstable in air, the sample was handled in a glove box with a _N2 atmosphere.

<Production Example 6: Synthesis of Ba ₂ H ₃ X halogen mixture (X=Cl, Br, I)>
_BaH2 , _BaCl2 , _BaBr2 , and _BaI2 were mixed in a mass ratio of 3:x:y:1-(x+y) (0≦x≦1, 0≦y≦1, 0≦x+y≦1). The pelletized sample was sealed in a vacuumed quartz tube. It was heated in an electric furnace at 650°C for 20 hours. Because _BaH2 and the product are very unstable in air, the sample was handled in a glove box with a _N2 atmosphere.

<XRD measurement results>
The results of synchrotron radiation powder X-ray diffraction (XRD) measurements of Ba ₂ H ₃ Cl, Ba ₂ H ₃ Br, and Ba ₂ H ₃ I obtained in Production Example 1 are shown in Figure 1. In Figure 1, the vertical axis represents diffraction intensity, and the horizontal axis represents diffraction angle.
The a-axis length (a (Å)) _and c _- axis length (c (Å)) were calculated for _Ba2H3Cl , _Ba2H3Br , and _Ba2H3I obtained in Production Example 1, and _Ba2H3Cl obtained in Production Example 2, and _are shown in Table _1. In Table 1, the values shown in the column labeled "ICSD" are those listed in the Inorganic Crystal Structure Database (ICSD) for each compound.
The results shown in Table 1 show that the c-axis length values differ from the values listed in the ICSD whether synthesized at normal pressure or at high pressure.
The results of synchrotron radiation powder X-ray diffraction measurement (XRD) of LaSrH ₃ S obtained in Production Example 4 are shown in FIG. 2, and the results of synchrotron radiation powder X-ray diffraction measurement (XRD) of Sr ₇ H ₁₂ Cl ₂ (Sr ₂ H _3.43 Cl _0.57 ) obtained in Production Example 5 are shown in FIG. 3.
FIG. 2 shows the Miller index corresponding to each peak.
3, SrO is presumed to be contained in the starting material SrH ₂ (purity 99.5%). Kapton tape is an air-blocking tape used when measuring air-labile samples.

Table 2 below shows the lattice constants obtained by LeBail analysis using X-ray diffraction data of a powder sample of the Ba ₂ H ₃ X halogen mixture (X=Cl, Br, I) obtained in Production Example 6.
Table 2 also lists data for single crystals that have already been reported for comparison.
The Ba ₂ H ₃ X halogen mixture (X=Cl, Br, I) obtained in Production Example 6 contains a considerable amount of Ba ²⁺ and 2H ⁻ Schottky defects.

<Electrochemical Impedance Measurement>
The sample pellets (4-10 mm diameter, 1-3 mm thickness) obtained during synthesis were used as they were for conductivity measurements. Au or Mo electrodes were attached to both sides of the sample pellet by vapor deposition or sputtering. Electrochemical impedance measurements were performed using a Bio-Logic VSP-300 in a hydrogen atmosphere, in the frequency range of 0.1-10 MHz, and during the heating and cooling process from room temperature to 400°C.

FIG. 4 shows the _results of _{electrochemical impedance} measurements ₍ Arrhenius plots) of _Ba2H3Cl , _Ba2H3Br , and _Ba2H3I obtained in Production Example 1, _{Ba1.9K0.1H2.9Cl} obtained in Production Example ₃ , and _LaSrH3S and _LaBaH3S obtained in Production Example 4.
For comparison, FIG. 4 also shows the hydride ion conductivities (Arrhenius plots) of BaH ₂ , La _0.6 Sr _1.4 LiH _1.6 O ₂ , La _0.6 Sr _1.4 LiH _1.6 O ₂ , LaH _2.52 O _0.24 , and LaHO.
From the above results, it is clear that the hydride ion conductor of the present invention has high hydride ion conductivity, and that the hydride ion conductor synthesized by the synthesis method under atmospheric pressure has particularly excellent hydride ion conductivity.
In particular, it is clear that the hydride ion conductor synthesized in Production Example 1 is capable of hydride conduction even in a low temperature range of 100° C. or less.

FIG. 5 shows the results (Arrhenius plots) of electrochemical impedance measurements of Ba ₂ H ₃ Cl, Ba ₂ H ₃ Br, and Ba ₂ H ₃ I obtained in Production Example 1 during temperature increase (FIG. 5A) and temperature decrease (FIG. 5B).
Table 3 also shows the hydride ion conductivity at 300° C. and activation energy of each compound.
The measurement conditions were as follows: The measurement was carried out under a _H2 atmosphere.
Measurement voltage: 500 mV
Frequency range: 7MHz to 0.1Hz
Electrode: Au electrode/sample/Au electrode Heating means: IR heater FIG. 6 shows the results of electrochemical impedance measurement (Cole-Cole plot) of Ba ₂ H ₃ I (200° C.) obtained in Production Example 1.

7 shows the results of electrochemical impedance measurement (Arrhenius plot) of Ba ₂ H ₃ X (X = Cl, Br, I) obtained in Production Example 6. Table 4 shows the hydride ion conductivity and activation energy at 300°C for each compound. All samples with any halogen mixing ratio showed a stable high ion conductivity exceeding 10 ^-3 S/cm (300°C).

From the above results, it can be seen that in this compound, the larger the ionic radius of the halogen ion, the higher the hydride ion conductivity and the smaller the activation energy.

From the above results, it was confirmed that the hydride conductor represented by formula (1) of the present invention has hydride conductivity.

The hydride ion conductor of the present invention is a composition that is expected to be used in various fields such as chemical synthesis and energy devices.
Therefore, the present invention has high industrial applicability.

Claims (15)

A hydride ion conductor having a composition represented by formula (1'): M ¹ _a-δ1 M ² _b-δ2 M ³ _c-δ3 H _{x-(δ1+2δ2+3δ3)} X ¹ _y X ² _z ;
In formula (1'), M1 ^represents an alkali metal element, ^M2 represents Mg or an alkaline earth metal element, M3 ^represents a rare earth metal element, 0≦a≦1, 0≦b≦2, 0≦c≦2, 1<a+b+c≦2, 0<x<4, X1 is a ^halogen element, 0≦y<4, X2 ^is a chalcogen element, when ^X2 represents only oxygen, 0≦z<1, when ^X2 represents an element containing a chalcogen element other than oxygen, 0≦z<3, 3<x+y+z≦5, and M1 ^, M2 ^, M3 ^, X1 ^and X Each of ^{δ1 and δ2} may contain a plurality of elements, δ1 is 0.1 or more, δ2 is 0.1 or more, δ3 is 0.1 or more, and a1-δ1, b1-δ2, c1-δ3, and x-(δ1+2δ2+3δ3) are not less than 0. 2. The hydride ion conductor according to claim 1, which does not contain oxygen atoms or contains oxygen atoms in an amount of 5% or less by mole relative to the total molar amount of ^X1 and ^X2 . The hydride ion conductor according to claim 1 or 2, wherein the absolute value of a + 2b + 3c - (x + y + 2z) is 1 or less. The hydride ion conductor according to any one of claims 1 to 3, which is a layered compound, and in which elements present in the layered compound among H, ^X1 and ^X2 in said formula (1) are present between the layered lattices. A hydride ion conductor according to any one of claims 1 to 4, wherein a = 0 in formula (1). 6. The hydride ion conductor according to claim 1, wherein in formula (1), 0<b≦2, and M ² contains at least one of Ba and Sr. 7. The hydride ion conductor according to claim 1, wherein in formula (1), 0<c≦2 and ^M3 contains La. The hydride ion conductor according to any one of claims 1 to 7, wherein, in formula (1), 0≦c≦1 and 1≦b≦2. 9. The hydride ion conductor according to claim 1, wherein in formula (1), 0<y<4, and X ¹ contains F, Cl, or Br. 10. The hydride ion conductor according to claim 1, wherein in formula (1), 0<z<3, and ^X2 contains S or Se. A method for producing the hydride ion conductor according to any one of claims 1 to 10 , comprising the steps of:
A step of heating a precursor powder containing at least one hydride composed of a binary system of A-H and at least one compound composed of a binary system of A-X under a pressure condition of less than 1 GPa,
A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
Method for producing hydride ion conductors. A method for producing the hydride ion conductor according to any one of claims 1 to 10 , comprising the steps of:
a step of heating a precursor powder containing at least one hydride composed of a binary system of A-H and at least one compound composed of a binary system of A-X under a pressure condition of 1 GPa or more,
A represents an alkali metal element, Mg, an alkaline earth metal element, or a rare earth element, and X represents a halogen element or a chalcogen element.
Method for producing hydride ion conductors. A catalyst comprising the hydride ion conductor according to any one of claims 1 to 10 . A battery electrolyte comprising the hydride ion conductor according to any one of claims 1 to 10 . A battery comprising the battery electrolyte of claim 14 .